Engine exhaust system and control



Aug. 26,1969 (5. l... SCHNURMACHER 3,462,945

ENGINE EXHAUST SYSTEM Ami) CONTROL Filed Nov. 24. 1967 INVENTOR GERALD L. SCHNURMACHER ,M/r M ATTORNEYS United States Patent M 3,462,946 ENGINE EXHAUST SYSTEM AND CONTROL Gerald L. Schnurmacher, 319 Bonita Ave., Piedmont, Calif. 94611 Filed Nov. 24, 1967, Ser. No. 685,422 Int. Cl. F01n 1/14, 3/10 US. CI. 60-30 4 Claims ABSTRACT OF THE DISCLOSURE In a vehicle exhaust system, the exhaust fluids are heated by hot input air blown into the exhaust channel. Input air is heated and blown into the exhaust channel by a blower and heater which operate whenever the exhaust channel temperature falls below a predetermined level, except for short periods during starting of the engine.

Background of the invention This invention pertains to engine exhaust systems and more particularly to an arrangement cooperating with such exhaust systems serving to maintain engine exhaust fluids in a vaporized state while discharging them to the outside surroundings.

It has been observed that a common failure in most exhaust systems is the mufller (or resonator, if one is provided), or the exhaust pipe leading along the underside of certain vehicles powered by internal combustion engines. It has been further observed that the cause of such failures frequently is to be found in deterioration of the metal components thereof as by rusting, chemical attack, or like deterioration such as may be caused by corrosive engine exhaust fluids accumulating and condensing in the system due to incomplete combustion and expulsion.

Objects I have observed that where an internal combustion engine is operated for relatively short periods which are insufficient to heat and fully vaporize the exhaust fluids, limited accumulations of condensed exhaust vapors may be retained in the exhaust system. This condensate may frequently have an acidic characteristic capable of attacking the metal components of the system.

In general, it is an object of the present invention to provide an improved automotive exhaust system for internal combustion engines whereby the tendency for such systems to accumulate exhaust fluid condensate and to retain same within the system shall be overcome.

It is another object of the invention to provide means for insuring that the discharging fluids of an internal combustion engine will be maintained at an elevated temperature sufiicient to vaporize all liquid therein and in conjunction therewith to forceably discharge such vapors from the system so that notwithstanding those short periods of operation of the engine which are inadequate to elevate the temperature of the system to a point where the exhaust fluid would normally be vaporized, the exhaust fluids will nevertheless all be vaporized and discharged.

It is another object of the invention to provide means of the kind described above wherein notwithstanding the de-energization of the ignition system of the engine upon stopping the vehicle, the apparatus as described herein will continue for a short post-operative period and thereby continue to vaporize and discharge engine fluids whenever the engine has been shut down at the end of such short periods of operation and in this manner serve to insure 0 against accumulation of fluid condensate 1n the exhaust 7 system.

3,462,946 Patented Aug. 26, 1969 Summary of the invention In general, in combination with an internal combustion vehicle engine having an electrical power supply for the engine and means forming exhaust channels from the engine, there is provided an electric heater element in conjunction with an electric blower located upstream from said heater. It is the purpose of the heater to elevate the discharge of the blower to a temperature sufiicient to heat the exhausting fluids of the engine to a point serving to vaporize substantially all the liquid of the fluids and to forcefully discharge the vaporized fluids along the exhaust channels to the outside surroundings. The engine exhaust system components, after reaching a predetermined temperature adequate to insure vaporization of all exhaust fluids, will retain the heat and develop a natural circulation serving to carry on this discharge and vaporizing function by themselves. Thus, a temperature responsive switch serves to detect the temperature of the exhaust fluids of the system and upon reaching a predetermined temperature serves to decouple (and de-energize) the heater element and blower from the vehicle power supply.

In addition, means are provided serving to momentarily defer energizing of the blower and heater during periods of operation of the starting motor 24. Also, means are provided whereby upon completion of short trips by vehicle 10 before the engine 11 has gotten the exhaust system hot enough to vaporize the exhaust fluids, the blower 17 and heater 18 will remain energized for a short period to further discharge accumulated vapors from the exhaust system.

Description of the preferred embodiment More particularly, the foregoing general arrangement is shown in the figure wherein a vehicle 10 carries a portion of an automotive engine schematically represented by the block 11. An exhaust manifold 12 serves to carry engine exhaust fluids along a channel defined by manifold 12, exhaust pipe portion 13, a mufller 14 and a tailpipe 16. This exhaust system forms a flow passage substantially continuously open to the outside surroundings of the vehicle.

In cooperation with the foregoing conventional components of an automotive exhaust system, there is provided an electrically operated blower 17 and an electric heater element 18 disposed to heat the output of blower 17 to a level adequate to heat the exhausting fluids of engine 11 to a point sufliciently high enough to vaporize all liquid components thereof. Blower 17 takes suction from the atmosphere and its discharge further serves to forceably discharge these vaporized components outwardly of the system along the continuously open path defined via muffler 14 and tailpipe 16.

Thus, in the figure, blower 17 is shown disposed in a housing 19 adapted for mounting either to engine 11 or to other portions of vehicle 10 carrying engine 11. Blower 17 and heater element 18 are disposed in an input channel defined by the hollow leg 22 leading into exhaust pipe 13. Leg 22 is disposed at such an angle, and suitably isolated from the main exhaust stream by baffle 20, so as to prevent the normal flow of fluids along the exhaust channel from discharging to the atmosphere reversely along hollow leg 22, blower housing 19, and blower 17.

Electric heater element 18 serves to heat the discharge of blower 17 immediately downstream thereof and is disposed in leg 22 whereby a flow of heated fluids passes into and heats the main stream of the exhaust system upstream of mufiier 14.

These heated gases serve to heat the components of the exhaust system whereby they can maintain the exhaust fluids in a vaporous phase.

Means for operating blower 17 and heater element 18 includes the electrical system now to be described.

A battery 23 forms a power supply to operate that portion of the ignition system operating engine 11 and starter motor 24, as well as to provide the power to operate blower 17 and heater element 18. In order to operate starter motor 24, an ignition switch 26 is moved to one of its two positions, as by means of a key. Switch 26 comprises of a pair of armatures ganged together whereupon activation of the starter switch 27 serves to energize starter motor 24. Then by suitable mechanical means represented by the dotted line 30, motor 24 initiates operation of engine 11.

Means are provided whereby during the aforementioned period of starting, power supply 23 will not be required to supply power for operating blower 17 and electric heater element 18.

Thus, when ignition switch 26 is turned on, capacitor 29 is charged slowly through resistor 28 thereby providing a suitable time delay as follows.

It is only when capacitor 29 becomes charged to a level of approximately six volts that it will operate transistor 31 by virtue of the bias which capacitor 29 applies to lead 33. The base electrode 35 of transistor 31 acts as a current amplifier to cause transistor to conduct. Zener diode 38 conducts only after capacitor 29 becomes charged to approximately six volts, so that transistor 40 will be biased into conduction via Zener diode 38, only after the short delay required to charge capacitor 29.

When so charged, transistor 40 will be biased into conduction to pass current through relay coil 37. Coil 37 closes switch armature 41 to connect lead 42 to the hot side of storage battery 23.

The temperature responsive switch means 34 is comprised of a temperature responsive bimetallic element 36 carried in the tailpipe section 16 of the exhaust channel. Element 36 is movable downwardly as shown in the figure in response to elevated temperatures applied thereto via the exhaust fluids passing from tailpipe section 16. Such movement of element 36 serves to open the switch armature 39 and thereby decouple blower 17 and heater element 18 from power supply 23. However, in its normal (cold) position, switch armature 39 is closed in a manner to complete the circuit from lead 42 to lead 45 and thereby carry power to blower 17 and heater element 18.

Thus, when the engine and exhaust system are cold, heater 18 and blower 17 will act to remove vapors from the system. However, whenever the system has been heated above a predetermined level (for example, sutiiciently well above 212 F. so as to insure vaporization of liquids in the exhausting fluids) the blower and heater are not particularly needed at such times and armature 39 will be moved by element 36 to open the lead 42.

Relay armature 41 is connected to the hot side of battery 23 irrespective of polarity in any suitable known fashion and lead 45 is connected to ground. Lead 25 is connected to plus twelve (+12) volts DC and lead is connected to minus twelve (-12) volts DC. If this is done, the system will be suitable for vehicles with either a positive or negative polarity ground, with no changes required.

As noted above, capacitor 29 interposes a short time delay adequate to accommodate starting the engine by the closure of starter switch 27 coupled to operate the starting motor 24. Capacitor 29 further serves, when needed, to prolong the operation of the blower and heater following turn off of ignition switch 26 so as to cause blower and heater to discharge any lingering vapors from the system.

Thus, means are provided whereby subsequent to turning off the engine, blower 17 and heater element 18 will be continued in an energized state. Accordingly, where the engine has been run only a very short period of time, insufficient to elevate the temperature of the exhaust fluids being discharged by the engine to a vaporizing level, it is an object of the present invention to insure against leaving such condensate in the exhaust system as may accumulate under these conditions.

Accordingly, means are provided for continuing the operation ofblower 17 and heater element 18 for a short period notwithstanding movement of the ignition switch 26 to a position serving to turn off the engine 11.

It is to be understood that ignition switch 26 serves to control the operation of the engine in conventional fashion. Thus, moving the ignition switch 26 to the off position not only serves to turn oif the engine, but also causes capacitor 29 to slowly discharge via resistor 43 thereby providing a short delay until the charge drops below a predetermined level. Upon passing below such level, transistors 31 and 40 will cease to conduct thereby de-energizing blower 17 and heater 18 as relay coil 37 releases armature 41 to be opened by spring 44.

It is to be noted that in the event that engine 11 has been operated sufficiently long to have provided exhaust fluids of a sufficiently elevated temperature to have opened switch armature 39, the foregoing feature will be unnecessary.

Therefore, the above arrangement serves to function only during those periods when it is necessary as where engine 11 has been operated for only a short time. Thus, where an automobile, for example, is operated to make a short trip to the grocery store and return, the foregoing feature will be called into play. On the other hand, after an extended trip, the exhaust temperatures will be sufficiently elevated to insure vaporization of all exhaust fluids.

From the foregoing, the operation of the overall system can be summarized as now to be described.

It is initially to be assumed that the system is in its initial state wherein the bimetallic temperature responsive element 36 is cool and thereby acting to close armature 39. Upon operation of ignition switch 26 by means of a drivers key depression of starter switch 27 serves to start engine 11. During this period of time, delay control means in the form of the charging capacitor 29 is effective to preclude completion of the blower and heater circuit from power supply 23.

Ultimately, however, the voltage buildup on capacitor 29 serves to operate coil 37 to close armature 41 and thereby establish a circuit via armature 41 along line 42. Once coil 37 has been energized, blower 17 and heater element 18 will become solely dependent upon the operation of switch armature 39 which responds to the temperature of the exhaust stream in tailpipe 16.

Preferably, heat responsive element 36 is arranged so that it calls heater element 18 and blower 17 into operation at a temperature level suflicient to insure adequate heating of the exhaust fluids to insure that substantially all liquid components thereof will be vaporized. Blower 17 has, of course, suflicient force to forcibly discharge all vapor from the exhaust channel.

From the foregoing, it will be readily apparent that there has been provided an exhaust system in combination with a vehicle engine whereby the exhaust fluids of the engine will essentially all be vaporized and positively blown from the exhaust system piping. By insuring against the condensing of such exhaust fluids and the accumulation therein of exhaust condensate, the life of the exhaust system is considerably extended.

By heating the input stream provided by blower 17 and then merging the hot input stream with the exhaust, the blower serves to more uniformly distribute the heat along the exhaust channel to insure vaporization and discharge of any corrosive exhaust liquids.

I claim:

1. In a vehicle the combination comprising an electrical power supply, an internal combustion engine of a type discharging exhaust tfluids comprised mainly of gas but including limited amounts of liquid, an exhaust manifold and means forming an exhaust channel leading therefrom to the outside surroundings, an electric blower serving to discharge a stream of air into said channel, an electric heater element disposed at a position to heat said blower stream being discharged into said channel, and means directing said heated discharge into said channel to cause the heated blower discharge to vaporize liquid in said channel and carry said vaporized liquid along said channel to the outside surroundings, and temperature responsive means disposed to sense the temperature of the exhaust fluids of said engine and serving to operate said heater element and blower conjointly from said power supply in response to fluid temperatures below a predetermined level sufficient to vaporize said liquid.

2. In combination, an engine of a type discharging exhaust fluids comprised mainly of gas but including limited amounts of liquid, an exhaust channel for exhausting the fluids from the engine, means forming a portion of an ignition system for operating the engine including an electric power supply and an ignition switch movable between first and second positions to control said engine, a blower serving to direct an input stream of gas into said exhaust channel, an electric heater element disposed to heat said stream to a level serving to cause said stream to vaporize liquid in said channel, said blower serving to discharge said vaporized liquid from said channel to the outside surroundings, temperature responsive switch means serving to couple said heater element and blower to be energized by said power supply in response to those temperatures of said exhausting fluids below a level sufficient to vaporize liquid in said exhausting fluids, and means serving to continue operation of said heater and blower for a relatively short period following termination of operation of said engine so as to discharge lingering fluids from said exhaust channel.

3. In combination, an engine of a type discharging exhaust fluids comprised mainly of gas but including limited amounts of liquid, means for starting and operating the engine, an electric power supply, ignition switch means movable between first and second positions said first position serving to couple the first said means to said power supply for starting and operating the engine, said second position serving to terminate operation of the engine, a channel exhausting said fluids from the engine to the outside surroundings, an electric heater element and an electric blower operably coupled to be energized by said power supply upon moving said ignition switch to said first position, said electric heater provided to heat the discharge of said electric blower, said heated blower discharge being disposed to heat fluids expelled by said engine along said channel to levels sufficient to vaporize any liquids therein, said heated blower discharge serving additionally to provide adequate force to blow said vaporized fluids along said channel, delay means serving to delay coupling of said heater element and said blower to said power supply for a period suflicient to accommodate prior operation of the first named said means by said power supply, and means responsive to the temperature of the exhausting fluids serving to deenergize said heater element and blower during periods when said temperature exceeds a level suflicient to insure vaporization of liquid in said exhausting fluid.

4. Apparatus according to claim 3 further including means serving to continue operation of said heater and blower for a relatively short period following termination of operation of said engine so as to discharge lingering liquid from said exhaust channel.

References Cited UNITED STATES PATENTS 2,864,960 12/1958 Linde --30 3,338,682 8/1967 Fowler 60-30 CARLTON R. CROYLE, Primary Examiner DOUGLAS HART, Assistant Examiner 

